Using Javascript array objects

Add common properties for Array object instances.

The prototype object.

The Array object have a prototype property which is a reference
to an object that contains common properties for all
object instances you creates out of the Array object.

All created array object instances has a hidden reference to this prototype object, but you don't need to
use that. You can access the common properties directly through the array object instance variable.

You must use the keyword 'this', which is a reference to the object
you have created out of an Array object, to get access to all the common properties.

Create common properties for all array instances.

There are two main ways to add new common properties for all array instances: